A Medaka fish embryo flown aboard space shuttle Columbia.

From NASA:
Launched on June 20, 1996, the STS-78 mission’s primary payload was the Life and Microgravity Spacelab (LMS), which was managed by the Marshall Space Flight Center (MSFC). During the 17 day space flight, the crew conducted a diverse slate of experiments divided into a mix of life science and microgravity investigations. In a manner very similar to future International Space Station operations, LMS researchers from the United States and their European counterparts shared resources such as crew time and equipment. Five space agencies (NASA/USA, European Space Agency/Europe (ESA), French Space Agency/France, Canadian Space Agency /Canada, and Italian Space Agency/Italy) along with research scientists from 10 countries worked together on the design, development and construction of the LMS. This photo represents the development of Medaka Fish Embryos, one of the many studies of the LMS mission.